Manipulate full text of a PDF

I'm going to manipulate the full text content of a PDF file created during export. Using "void InsertChar(int lCode, int lConfidence, int bNewWord, int lLeft, int lTop, int lRight, int lBottom)" CCO API call I can add new words to the CCO. I can automatically create new fields, and fill these fields from the CCO. And finally I can put these words into the PDF using dcpdf_MakePDFDoc (). OK. But how can I delete words from the CCO?